/*
 * File      : posix_mmap.c
 * This file is part of RT-Thread RTOS
 * COPYRIGHT (C) 2017, RT-Thread Development Team
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Change Logs:
 * Date           Author       Notes
 * 2017/11/30     Bernard      The first version.
 */

#include <stdint.h>
#include <stdio.h>

#include <rtthread.h>
#include <dfs_posix.h>

#include <sys/mman.h>

void* mmap(void* addr, size_t length, int prot, int flags,
           int fd, off_t offset)
{
	uint8_t* mem;

	if(addr) {
		mem = addr;
	} else mem = (uint8_t*)malloc(length);

	if(mem) {
		off_t cur;
		size_t read_bytes;

		cur = lseek(fd, 0, SEEK_SET);

		lseek(fd, offset, SEEK_SET);
		read_bytes = read(fd, addr, length);

		if(read_bytes != length) {
			if(addr == RT_NULL) {
				/* read failed */
				free(mem);
				mem = RT_NULL;
			}
		}

		lseek(fd, cur, SEEK_SET);

		return mem;
	}

	errno = ENOMEM;

	return MAP_FAILED;
}

int munmap(void* addr, size_t length)
{
	if(addr) {
		free(addr);
		return 0;
	}

	return -1;
}
